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ENVIRONMENTAL ENGINEERING-I
INTRODUCTION
Human activities and environment pollution
Humans impact the environment in several ways. Common effects include decreased
water quality, increased pollution and greenhouse gas emissions, depletion of natural resources
and contribution to global climate change. Some of these are the direct result of human activities,
whereas others are secondary effects that are part of a series of actions and reactions.
Water Pollution
Perhaps the most obvious examples of a negative human impact on the environment is water
pollution. It's obvious we need water to survive but few people realize how much we need and
just how much is available. Consider these facts from the United Nations Environment
Programme:
1
Of all the water on Earth, only 2.5% of it is freshwater.
2
Of that 2.5%, less than 1% is available to us.
3
Humans each require up to 13 gallons (50 litres) a day of fresh water for drinking,
cooking and cleaning. This does NOT take into account the countless gallons of water
needed to grow food or care for animals.
4
70% of all freshwater usage goes to irrigation.
According to Organic Farming Research Foundation, only 2% of farms are organic. This equates
to almost 69% of our freshwater supply is being contaminated by chemical pesticides, herbicides,
and chemical fertilizers, while also compounded with fossil fuels and emissions from heavy
farming machinery. These chemical compounds contribute to acid rain. Since very little can live
in an acidic environment, acid rain has harmful effects on plants, animals, and aquatic life, as well
as humans and even buildings, statues or other objects. Acid rain also contaminates our limited
freshwater supply, and thus the cycle of water pollution continues. According to the U.S.
Environmental Protection Agency, 45% of assessed stream miles, 47% of assessed lake acres, and
32% of assessed bay and estuarine square miles were not clean enough to support uses such as
swimming or fishing. The following reasons and possible sources for this include: Sediments,
pathogens and habitat alterations from agricultural activity and hydrologic modifications (such as
dams Excessive nutrients, metals and organic enrichment from agricultural activity and
Dept. civil engg. ACE, Bangalore
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Intake structures – different
types of intakes; factor of selection and location of intakes. Pumps- Necessity, types –
power of pumps; factors for the selection of a pump. Pipes – Design of the economical
diameter for the rising main; Nomograms – use; Pipe appurtenances.